Despite the prevalence of hyperactivity in school-age children, few attempts have been made to identify or treat this disorder prior to school entrance. Parent reports, however, suggest that in most cases hyperactivity and associated distractibility, impulsivity, and disciplinary problems are present in some form from infancy or early childhood onward. Follow-up studies of preschool and school-age hyperactive children further suggest that this disorder persists and is relatively resistant to treatment. Thus, the present research is aimed at early identification and treatment of childhood hyperactivity. In the first phase, a sample of 2 1/2 to 3 years old hyperactive toddlers would be recruited and matched with non-hyperactive controls. They would then be compared on a variety of parent report, family history, behavioral, and cognitive measures to determine how young hyperactive children and their parents actually differ from controls. This would provide data on the correlates of hyperactivity in toddlers and the usefulness of certain assessment devices with this age group. The second phase of the project would evaluate the efficacy of parent training groups as an intervention strategy with toddlers. The effectiveness of behavioral, behavioral plus self-control, and non-directive parent training would be compared with a waiting list control. Therapeutic effect would be evaluated immediately at the conclusion of treatment and in a six month post-treatment follow-up to assess short-term gains and maintenance of change in child behavior and parent management skills.